Devices for the reproduction of music and other sounds, either broadcast or reproduced from magnetic tape or disc, are increasingly popular forms of recreation and cultural development. High fidelity stereophonic systems, in particular, have grown into a form of mass leisure and become the basis of a strongly growing audio industry.
The present invention relates generally to audio reproduction systems, and particularly to systems of the high fidelity type, which are essentially concerned with the faithful recreation of sound events or, more exactly, with the recreation of sound sensations that is as close as possible to the sound sensations that a listener would have received at the place and time of the original event, with regard to frequency range, dynamics, impulse behaviour, noise, distortion (or shortly, sound quality) and, most of all, in the case of stereophonic systems, with the local (space) and temporal (phase, delay) determinants of the sound sensations. Totally, high fidelity stereophonic systems should be able to provide the whole depth and detail that the human ear can detect in the presence of original sound events. Such a task, obviously, can only be achieved through the use of particular and partly complex high fidelity technologies.
The invention relates further to battery-operated cassette devices of stereophonic high fidelity type, and to high fidelity earphone and headphone applications and to the art of binaural stereophonic reproduction in general.